Mechanical Brake Actuator

ABSTRACT

To provide the mechanical brake actuator enabling to downsize the device and to reduce the manufacturing costs of the parts. The mechanical brake actuator comprises the strut ( 23 ) which engages with one brake shoe ( 12 ) and has two facing plates ( 23 b) with a strut-bridge ( 23 a) connecting therebetween and the plate-like brake lever ( 24 ) which engages with the other brake shoe ( 13 ). The brake lever ( 24 ) is retained in the space ( 23 c) between the facing strut plates and is pivotally supported on the strut ( 23 ), and the inner cable ( 41 ) of the brake cable ( 40 ) connected to the free end ( 24 e) of the brake lever ( 24 ) via the connecting pin ( 43 ). The mechanical brake actuator which is operated by pulling the inner cable ( 41 ) comprises the clip ( 30 ), which attaches to the strut-bridge ( 23 a) and restricts the rotation of the brake lever ( 24 ) in the cable releasing direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a mechanical brake actuator providing an easypreventive measure for brake cable disengagement.

2. Description of the Related Art

This type of brake actuator is comprised of a plate-like brake lever, astrut pivotally retained the brake lever therein, and a pivotal pin,wherein the mechanical actuator is positioned between a pair of brakeshoes, and the brake lever and the strut relatively rotates asoperating, i.e., pulling a brake cable connected to the brake lever,while spreads the brake lever and the strut apart from each other in anopposite direction.

Then, after engaging the brake cable with the brake lever as inserting aconnecting pin in a brake cable-connecting hole of the brake leverexposed out from an opening of the strut, a C-like bending clip attachesto an exterior of facing plates of the strut, and concaves formed onboth inner surfaces of the clip engage with convexes formed on bothouter surfaces of the strut to position the brake lever within the spaceof the strut via the clip. The basic structure of this is disclosed inthe paragraphs 0015-0016 and FIGS. 2-4 of the Japanese ProvisionalPatent Publication No. 2001-349360.

Instead of the above-described structure, the paragraphs 0020-0023 andFIGS. 5-8 of the same reference shows that the clip is assembled on theexterior of the facing plates of the strut as rotatably attaching to thestrut.

Problems to be resolved by this invention are as follows:

-   (1) An independent clip is more complex in assembly and leaves a    possibility of losing the clip and/or to neglect the clip    assembling.-   (2) If the clip is assembled on the strut, a rotational axis needs    to be on both outer surfaces of the strut, which increases the cost    of manufacturing.-   (3) Because of providing the convex and the rotational axis on the    strut, high accuracy in the formation of the projection and the    rotational axis (i.e., coaxially) is necessary, which requires    higher manufacturing accuracy.-   (4) At least, the clip plate thickness becomes easily interfering    with nearby parts such as a shoe return spring adjacent to the    strut.    Therefore, operability as attaching the clip to the strut is    jeopardized, and there is a possibility of nearby parts being    obstacles, which prevent the clip from attaching to the strut.-   (5) The clip needs to be widened so as to attach to the exterior of    the strut.    Thus, a material cost of the clip increases, and a manufacturing    cost of the clip increases due to the necessary high accuracy of    providing the concave and the rotational axis in the clip (i.e.,    coaxially).-   (6) For the independent clip, when attaching the clip to the strut,    side surfaces of the clip needs to be pushed out to spread open and    maintained the condition by fingers until traveling over the convex    of the strut, and the respective concave of the clip is arranged to    fit on the convexes of both sides of the strut, which jeopardizing    the operability of the clip attaching operation.

This invention was made inconsideration of the above problems, and anobject of this invention is to provide the mechanical brake actuatorrealizing the miniaturization of the entire device and the reduction ofthe parts costs. Furthermore, another object of this invention is toprovide the mechanical brake actuator remarkably improving the clipattaching operation.

SUMMARY OF THE INVENTION

In order to attain the above objects, a mechanical brake actuatorrelated to this invention is characterized to comprise a strut that hastwo facing plates with a strut-bridge connecting therebetween and thatengages with one brake shoe, and a plate-like brake lever that engagesthe other brake shoe, in which the brake lever is retained in a spacebetween the facing plates of the strut and is pivotally supported in thestrut at a proximal end thereof, and the brake lever and the strutrelatively rotate to spread apart from each other while pulling a brakecable connected to a free end of the brake lever via a connecting pin,wherein a clip, which restricts rotation of the brake lever in a cablereleasing direction, attaches to the strut-bridge. In this invention,simply attaching the small size clip to the strut-bridge restricts therotation of the brake lever in the cable releasing direction, therebysurely preventing the disengagement of the brake cable from the brakelever.

Furthermore, this invention is characterized in that the above-describedmechanical brake actuator is structured such that the clip has a pair oflegs that clip on the strut-bridge.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that theclip slidably enfolds the strut-bridge.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that theclip has a positioning portion restricts the rotation of the brake leverin the cable releasing direction as abutting one portion of the legagainst the brake lever.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that theclip slidably enfolds the strut-bridge.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that theclip and the strut-bridge have two pairs of convexo-concave engagementand each pair of the convexo-concave engagement is to be selectable assliding the clip.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that aconnecting operation of the brake cable, the brake lever, and theconnecting pin is possible when the clip is in a retreat position, andthe clip restricts the rotation of the brake lever so as to disable theconnecting operation of the brake cable, the brake lever, and theconnecting pin when said clip is in a progress position.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that theclip rotatably attaches to the strut-bridge.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that theclip and the strut-bridge have a convexo-concave engagement, and theclip attaches to the strut-bridge as fitting the convexo-concavoportions.

Still further, this invention is characterized in that theabove-described mechanical brake actuator is structured such that theclip clips on the front and rear end edges of the strut-bridge.

Yet further, this invention is characterized in that the mechanicalbrake actuator is structured such that the connecting operation of thebrake cable, the brake lever, and the connecting pin is possible whenthe clip is at a position in the cable releasing direction side, and theclip restricts the rotation of the brake lever to disable the connectingoperation of the brake cable, the brake lever, and the connecting pinwhen the clip is at a position in the cable operating direction side.

This invention has the following advantages.

-   (1) When the clip attaches to the strut so as to restrict the    rotation of the brake lever in the cable releasing direction, the    convexes on both outer surfaces of the strut are not necessary,    which downsizes the entire width of the strut.-   (2) Because the clip attaches to the strut-bridge, the clip does not    interfere with the nearby parts adjacent to the strut.-   (3) The attaching operability of the clip can be improved by simple    operation of attaching the clip to the strut-bridge.-   (4) The position of the positioning portion of the clip for    determining the position of the brake lever can be changed by simple    operation of sliding or rotating the clip while fitting on the    strut-bridge, thereby facilitating the operation of engaging and    disengaging the cable end with/from the brake lever.-   (5) The clip attaches to the strut-bridge, which can downsize the    clip and manufacturing by simple bending process, thereby decreasing    the material cost and the manufacturing cost of the clip.-   (6) When the clip enfolds the strut-bridge of the strut, no    additional processing is necessary to the strut.-   (7) When the clip rotatably attaches to the strut-bridge, the clip    can be further downsized and manufactured by simple bending process,    thereby decreasing the material cost and the manufacturing cost of    the clip.    Furthermore, when the clip attached to the strut-bridge is rotated    by fingers to restrict the rotation of the brake lever in the cable    releasing direction, the attaching sound and the resulted vibration    make an operator to hear and feel the operation, thereby confirming    the clip installation.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects of the present invention will become readilyapparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a plan view of an example of the dram brake with themechanical brake actuator according to the first embodiment;

FIG. 2 is a cross section view of FIG. 1 taken along the line II-II;

FIG. 3 is an exploded perspective view of the mechanical brake actuatoraccording to the first embodiment;

FIG. 4 is a partially omitted perspective view of the strut-bridge ofthe strut;

FIG. 5 is a perspective view of a partially broken clip according to thefirst embodiment;

FIG. 6 is an explanatory view of the mechanical brake actuator structureand operation according to the first embodiment, which illustrates thecondition where the free end of the brake lever is exposed out from theopening of the space of the strut in the cable releasing direction side;

FIG. 7 is an enlarged view of the mechanical brake actuator structureand operation according to the first embodiment, which illustrates thecondition that the free end of the brake lever is exposed out from theopening of the space of the strut in the cable releasing direction side;

FIG. 8 is an enlarged view of mechanical brake actuator operationaccording to the first embodiment, which illustrates the condition thatthe clip disabling the brake lever rotation in the cable releasingdirection;

FIG. 9 is a perspective view of the clip according to the secondembodiment;

FIG. 10 is an enlarged view of the mechanical brake actuator structureand operation according to the second embodiment, which illustrates thecondition that the free end of the brake lever is exposed out from theopening of the space of the strut in the cable releasing direction side;

FIG. 11 is an enlarged view of mechanical brake actuator operationaccording to the second embodiment, which illustrates the condition thatthe clip disabling the brake lever rotation in the cable releasingdirection;

FIG. 12 is an enlarged view of the mechanical brake actuator structureand operation according to the third embodiment, which illustrates thecondition that the free end of the brake lever is exposed out from theopening of the space of the strut in the cable releasing direction side;

FIG. 13 is an enlarged view of mechanical brake actuator operationaccording to the third embodiment, which illustrates the condition thatthe clip disabling the brake lever rotation in the cable releasingdirection;

FIG. 14 is an enlarged view of mechanical brake actuator structure andoperation according to a modification of the third embodiment, whichillustrates the condition that the clip disabling the brake leverrotation in the cable releasing direction;

FIG. 15 is an enlarged view of mechanical brake actuator structure andoperation according to the fourth embodiment, which illustrates thecondition that the clip disabling the brake lever rotation in the cablereleasing direction;

FIG. 16 is an enlarged view of the mechanical brake actuator structureand operation according to the fifth embodiment, which illustrates thecondition that the free end of the brake lever is exposed out from theopening of the space of the strut in the cable releasing direction side;

FIG. 17 is an enlarged view of the mechanical actuator operationaccording to the fifth embodiment, which illustrates the condition thatthe clip disabling the brake lever rotation in the cable releasingdirection;

FIG. 18 is an enlarged view of the mechanical brake actuator structureand operation according to a modification of the fifth embodiment, whichillustrates the condition that the free end of the brake lever isexposed out from the opening of the space of the strut in the cablereleasing direction side;

FIG. 19 is an enlarged view of operation of the mechanical actuatingmechanism according to a modification of the fifth embodiment, whichillustrates the condition that the rotation of the brake lever in thecable releasing direction is disabled by the clip;

PREFERRED EMBODIMENTS OF THE INVENTION Embodiment 1

In the following sections, a mechanical brake actuator relating to thisinvention will be explained.

FIG. 1 is a plan view of an example of the drum brake device with themechanical brake actuator, FIG. 2 is a cross-sectional view of FIG. 1,and FIG. 3 is an exploded perspective view of the above-describedmechanical brake actuator.

The first embodiment of this invention will be explained with referenceto the drawings.

A pair of brake shoes 12 and 13 are movably mounted, via a shoe holdmechanism (not shown in the figures), on a back plate 11 which is fixedon a stationary portion 10 of a vehicle, and one pair of facing ends ofthe brake shoes 12 and 13 are supported by raised portion 16 a of alater described anchor 16 while the other pair of facing ends thereofare connected via a joint member. A pair of shoe return springs (whereonly one shoe return spring 19 of the two shoe return springs appears inthe figure), extended between both brake shoes 12 and 13, maintains acondition of abutment between both ends of both brake shoes 12 and 13and joint member and between both ends and the anchor 16.

A mechanical actuator 22 which expands one ends of both brake shoes 12and 13 is comprised of a strut 23, a brake lever 24, a pivot pin 25, anda washer 26, which is positioned adjacent to the raised portion 16 a ofthe anchor 16 between both brake shoes 12 and 13.

Furthermore, the strut 23 is designed such that a space is reservedtherein to surround the brake lever 24 and that a strut-bridge 23 aconnects two facing plates 23 b, 23 b of the strut 23 so that a clip 30for restricting the rotation of the brake lever 24 attaches to thestrut-bridge 23 a.

The strut 23 as a component of the mechanical actuator 22 is made of onepiece of plate, which is folded to make C-shape with two facing plate 23b, 23 b and has the strut-bridge 23 a at an intermediate portion of thestrut 23 in a longitudinal direction. Furthermore, one ends of thefacing plates 23 b and 23 b are superposed each other to be fixed suchas by welding. A wider space (clearance) 23 c reserved at a centralregion in the longitudinal direction between the two facing plate 23 b,23 b while a narrower space (clearance) 23 d than the space 23 c iscontinuously formed at the other ends thereof. A shoe engagement groove23 e is formed at the superposing portion at one end of the facingplates 23 b, 23 b while pivotal holes 23 f, 23 f are formed at the otherend thereof.

The strut bridge 23 a, bridging over upper portions of the facing plates23 b, 23 b, closes one section of the wider space 23 c. The strut-bridge23 a and the brake lever 24 are interrelated such that the brake lever24 does not abut against the strut-bridge 23 a until a brake cableconnecting hole 24 f formed at a free end 24 e of the brake lever 24, inits entirety, becomes exposed out from the wider space 23 c of the strut23. Because of the above-described structure, in particular the functionof the clip 30, a cable end 42 fixed at an end of an inner cable 41 doesnot physically disengage from the brake lever 24 during thetransportation of the drum brake device.

As shown in an enlarged view of FIG. 4, an outer and an inner surface ofthe strut-bridge 23 a, as a portion which the later described clip 30attaches, has a convex 23 i and a concave 23 k. These convex 23 i andconcave 23 k function to position the clip 30. Although when the convex23 i and the concave 23 k are formed on a coaxial line on thestrut-bridge 23 a, both convex 23 i and the concave 23 k cansimultaneously be formed by one press working, the positions of theconvex 23 i and the concave 23 k are not limited to be on the coaxialline and may be shifted in the longitudinal direction of the strut 23.

The brake lever 24 as the one component of the mechanical actuator 22 ismade of one piece of plate and positioned in the spaces 23 c, 23 d ofthe strut 23 so as to be retained therein. A shoe engagement groove 24 bis formed in a proximal portion 24 a of the brake lever 24, while apivot hole 24 d, though which a pivot pin 25 is penetrated, is formed inan upper leg 24 c. The pivot pin 25 is penetrated thorough pivot holes23 f, 24 d, 23 f of the strut 23 and the brake lever 24 and a washer 26is clipped on an end of the pivot pin 25, thereby pivotally supportingthe brake lever 24 relative to the strut 23. The brake lever 24 isrestricted its clockwise rotation in FIG. 2 as its end surface abuttingagainst the strut-bridge 23 a or the clip 30 attaches to thestrut-bridge 23 a. The brake cable connecting hole 24 f is formed at afree end 24 e of the brake lever 24, through which a connecting pin 43to connect the cable end 42 fixed to the end of the inner cable 41 as acomponent of a later described brake cable 40.

Also, the strut 23 and the brake lever 24, which constitute themechanical actuator 22, have lower legs 23 g and 24 h at a cableoperation side, which are slidably located on the heads of installationbolts 20, 21 as shown in FIG. 2.

The clip 30 is a member restricting the clockwise rotation in FIG. 2 ofthe brake lever 24 and slidably clips on the strut-bridge 23 a.

As shown in FIG. 5, the clip 30 of this embodiment, which is made of onepiece of steel spring plate strip and is rather narrower thancross-width of the strut-bridge 23 a, is bent and enfolded in U or Cshape and resiliently clips on the strut-bridge 23 a.

One leg 31 of a pair of facing legs 31, 32 which abuts against the outersurface of the strut-bridge 23 a has a positioning hole 31 a to freelyfit on the convex 23 i of the strut 23. The other leg 32 which abutsagainst an inner surface of the strut-bridge 23 a has an engaging convex32 a, which projects toward one leg 31 and fits in a concave 23 k of thestrut 23, and a positioning portion 32 b, which is formed by bending anend area thereof to greatly project in a direction to depart from oneleg 31.

The engaging convex 32 a and positioning hole 31 a of the clip 30individually fit in the concave 23 k and on the convex 23 i, which areformed on the inner and outer surfaces of the strut-bridge 23 a, therebypositioning the clip 30 on different positions on the strut-bridge 23 a.

When the clip 30 clips on the strut-bridge 23 a as fitting the engagingconvex 32 a of the clip 30 in the concave 23 k formed on the innersurface of the strut-bridge 23 a, the peripheral surface of the brakelever 24 directly abuts against the strut-bridge 23 a to restrict therotation of the brake lever 24.

Also, the clip 30 slides to fit the positioning hole 31 a on the convex23 i formed on the outer surface of the strut-bridge 23 a, theperipheral surface of the brake lever 24 abuts against the positioningportion 32 b of the clip 30 to restrict the rotation of the brake lever24. That is, in this example, by sliding the clip 30 clipping on thestrut-bridge 23 a forward and backward, the brake lever 24 is able toshift an allowable rotational position (rotation angle) thereof in thecable releasing direction in two stages (two positions).

The amount/distance of projection of the positioning portion 32 b of theclip 30 and the brake lever 24 are interrelated so that when theengaging convex 32 a of the clip 30 fits in the concave 23 k formed onthe inner surface of the strut-bridge 23 a to restrict the rotation ofthe brake lever 24, the entire brake cable connecting hole 24 f of thebrake lever 24 is to be exposed out from the wider space 23 c of thestrut 23, and when the positioning hole 31 a of the clip 30 fits on theconvex 23 i formed on the outer surface of the strut-bridge 23 a torestrict the rotation of the bake lever 24, one part of the brake cableconnecting hole 24 f formed in the free end 24 e of the brake lever 24is positioned in the wider space 23 c of the strut 23, therebypreventing the disengagement of the connecting pin 43 (see FIG. 8).

In order to advance an opening of the clip 30 to a side end of thestrut-bridge 23 a smoothly, the ends of both legs 31, 32 should be bentto spread out from each other, however, such an configuration is notnecessary.

The brake cable 40 illustrated in FIG. 2 and FIG. 3 is comprised of theinner cable 41 and an outer casing 44.

A process of connecting the brake cable will be explained next. FIG. 6is a view of the condition of the mechanical actuator 22 afterconnecting the brake cable 40 to the brake lever 24, and FIG. 7 is anenlarged view of the condition of the mechanical actuator 22 beforeconnecting the brake cable 40 to the brake lever 24. The legs 32, 31 ofthe clip 30 clip the inner and outer surfaces of the strut-bridge 23 a,and the engaging convex 32 a fits in the concave 23 k formed on theinner surface of the strut-bridge 23 a for positioning. The clip 30 ispositioned at an fitting section between the engaging convex 32 a andthe concave 23 k while the lateral movement is restricted with lightabutment between both side ends of the other leg 32 and sleeves of bothsides of the strut-bridge 23 a, thereby providing the stablepositioning.

The positioning portion 32 b of the clip 30 moves back to a positionclose to the concave 23 k of the strut-bridge 23 a, thereby nointerfering the positioning portion 32 b to the brake lever 24.

Accordingly, while the clip 30 is moved back relative to thestrut-bridge 23 a and is positioned there, the rotational range towardthe cable releasing direction of the brake lever 24 is restricted at theposition where an intermediate portion of the brake lever 24 abutsagainst the strut-bridge 23 a.

(See FIG. 7)

At this time, the free end 24 e of the brake lever 24 projects outtoward the cable releasing direction side from the opening of the widerspace 23 c of the strut 23, and the entire brake cable connecting hole24 f is exposed from the opening of the strut 23.

(See FIG. 7)

The inner cable 41 is pinched by fingers to be inserted in a guide pipe45, and the cable end 42 fixed at the end of the inner cable 41 passesthrough the wider space 23 c of the strut 23 to reach the free end 24 eof the brake lever 24.

Under the condition that the free end 24 e of the brake lever 24 ispositioned between a pair of end-legs 42 b, 42 b formed in the cable end42 and that a cable end connecting holes 42 c, 42 c and the brake cableconnecting hole 24 f are aligned, the connecting pin 43 is inserted inand through to establish the connection between the brake lever 24 andthe cable end 42.

When the cable end 42 is connected to the brake lever 24, as a right endof the clip 30 is pushed toward the free end 24 e of the brake lever 24to approach thereto as shown in FIG. 8, the clip 30 releases theengagement between the engaging convex 32 a and the concave 23 k formedon the inner surface of the strut-bridge 23 a. When the clip 30 isfurther pushed, the positioning hole 31 a formed in a clip 30 fits onthe convex 23 i formed on an outer surface of the strut-bridge 23 a, andthe positioning is completed at the position where the clip 30 isforwarded relative to the strut-bridge 23 a. Finally, a casing cap 44 aof the outer casing 44 is fixed at the other end of a guide pipe 45 witha ring 46. (See FIG. 2)

As the clip 30 slides to shift the clipping position to a position closeto the free end 24 e of the brake lever 24, the positioning portion 32 balso approaches to the free end 24 e of the brake lever 24. Accordinglythereafter, if the brake lever 24 rotates in the cable releasingdirection, the brake lever 24 abuts against the positioning portion 32 bof the clip 30, thereby restricting the further rotation thereof. (SeeFIG. 8) At this time, an allowable rotational range of the brake lever24 is smaller than the case that the brake lever 24 abuts against thestrut-bridge 23 a as shown in FIG. 7. As such, the connecting pin 43 isconstantly positioning in the wider space 23 c of the strut 23, and thecable end 42 will not physically be disengaged from the brake lever 24.

Also, when the cable end 42 needs to be disengaged from the brake lever24 for exchanging the brake cable 40, the clip 30, while clipping on thestrut-bridge 23 a, is moved backward to the pivotal side of the brakelever 24, and the brake lever 24 is rotated in the cable releasingdirection, thereby enabling to remove the connecting pin 43 easily.

In this example, the convex 23 i and the concave 23 k can be formed by asimple press work of the strut-bridge 23 a only, and high accuracy inmanufacturing the strut 23 as required in the conventional technology isnot necessary. Also, the clip 30 attaches to the strut-bridge 23 a, andunlike the conventional technology, does not interfere with nearby partssuch as shoe return spring adjacent to the strut 23, thereby designingthe entire width of the strut 23 narrower. Therefore, operability ofattaching the clip 30 remarkably increases. Furthermore, the amount ofspring steel usage for forming the clip 30 can be minimized, which iseconomical.

In the following section, the mechanical brake actuator relating to thesecond embodiment will be explained with reference to FIGS. 9-11.

The clip 50, which is used in this second embodiment, as shown in FIG.9, has one leg 51 abutting against the outer surface of the strut-bridge23 a which has a rectangular first positioning hole 51 a and a circularsecond positioning hole 51 b, which are formed with a predeterminedinterval therebetween in the longitudinal direction of the clip 50. Aninner edge of the first positioning hole 51 a at a side of the secondpositioning hole 51 b is cut and curved up to form a guide 51 c.

The guide 51 c at the inner edge of the first positioning hole 51 a,when the clip 50 is pushed in, functions so that the convex 23 i of theouter surface of the strut-bridge 23 a may project out from the firstpositioning hole 51 a smoothly as being guided on the guide 51 c, andthe first positioning hole 51 a with a round inner circumferentialsurface may be used instead of the guide 51 c. This guide 51 c makes theslide of the clip 50 easy.

In the process of attaching the clip 50, as described in the firstembodiment, the clip 50 is pressed to attach to the strut-bridge 23 afrom the side of the brake lever pivot hole of the strut-bridge 23 a,and a resilient force of the clip 50 is utilized to clip on thestrut-bridge 23 a.

After attaching the clip 50, the strut 23 is positioned by fitting thefirst positioning hole 51 a of the clip 50 relative to the convex 23 ion the outer surface of the strut-bridge 23 a. Accordingly, therotatable range of the brake lever 24 in the cable releasing directionis restricted by the position where the brake lever 24 abuts against thestrut-bridge 23 a. (See FIG. 10) When the brake lever 24 abuts againstthe strut-bridge 23 a, the entire brake cable connecting hole 24 fformed in the free end 24 e of the brake lever 24 is designed to bere-exposed out from the opening of the strut 23, thereby facilitatingthe connection of the brake lever 24 and the cable end 42 as insertingthe connecting pin 43.

When the connection between the brake lever 24 and the cable end 42 iscompleted, the clip 50 is further pushed to fit the second positioninghole 51 b on the convex 23 i on the outer surface of the strut-bridge 23a to change a clipping position of the clip 50 to nearby position of thefree end 24 e of the brake lever 24. (See FIG. 11) As the clippingposition of the clip 50 is changed, the positioning portion 52 b of theclip 50 approaches the free end 24 e of the brake ever 24, and as aresult, the rotatable range of the brake lever 24 is restricted at apoint of abutment with the brake lever 24 and the positioning portion 52b formed at the end of the other leg 52. Accordingly thereafter, therotation of the brake lever 24 is restricted by the positioning portion52 b of the clip 50, and the connecting pin 43 is constantly positioningin the wider space 23 c of the strut 23, so that the cable end 42 wouldnot physically be disengaged from the brake lever 24.

In this example, in addition to the same advantages as described in thefirst embodiment, there is an advantage of manufacturing of the strut 23being simple because only a process of forming the convex 23 i on thestrut-bridge 23 a is required.

The mechanical brake actuator relating to the third embodiment will beexplained with reference to FIG. 12 and FIG. 13.

This example shows not only the case that the clip 60 made of one pieceof spring steel by simply press work resiliently fits on the upper andlower surfaces of the strut-bridge 23 a but also the case that the clip60 enfolds the strut-bridge 23 a.

The clip 60 in this example has the pair of legs 61, 62, entire lengthof which is longer than the lateral width of the strut-bridge 23 a, andone leg 61 has a folded portion 61 d bending at an edge of thestrut-bridge 23 a as extending beyond therefrom. The other leg 62 hasthe positioning portion 62 d, which is defined by an extended portion ofthe other leg 62 bending from an edge of the strut-bridge 23 a asextending beyond therefrom toward a direction to spread apart from oneleg 61. The clip 60 of this example functions not only to enfold thestrut-bridge 23 a by cooperating the positioning portion 62 b and thefolded portion 61 d but also to act as a stopper restricting therotation of the brake lever 24 in the cable releasing direction.Therefore, in the condition that the clip 60 is enfolding thestrut-bridge 23 a, the amount/distance of extension of the positioningportion 62 b and the brake lever 24 are interrelated so as to restrictthe rotation of the brake lever 24 in the cable releasing direction asthe positioning portion 62 b interferes with the brake lever 24 at theposition where the entire brake cable connecting hole 24 f of the brakelever 24 is not exposed out from the opening of the strut 23.

In this example, before attaching the clip 60 to the strut-bridge 23 a,the connecting pin 43 is inserted to connect the brake lever 24 and thecable end 42 or the cable end 42 is connected to the brake lever 24while the clip 60 is clipping only a predetermined amount of thestrut-bridge 23 a at the position where the entire brake cableconnecting hole 24 f is exposed out from the opening of the strut 23 asshown in FIG. 12. After the connecting pin 43 is inserted to connect thecable end 42 and the brake lever 24, the clip 60 is pushed deep over toenfold the strut-bridge 23 a as shown in FIG. 13. After attaching theclip 60 to the strut-bridge 23 a, the positioning portion 62 b canrestrict the rotation of the brake lever 24 in the cable releasingdirection, and therefore the connecting pin 43 constantly positions inthe wider space 23 c of the strut 23, and the cable end 42 does notphysically disengage from the brake lever 24.

In this example, in addition to the same advantages of the abovedescribed first embodiment, no processing is necessary to be done on thestrut 23 and no hole is necessary to be formed on the clip 60, where thebending process is necessary, thereby offering an advantage to reducethe number of steps for manufacturing.

A modification to the mechanical brake actuator of the third embodimentwill be explained with reference to FIG. 14. The clip 60 in this exampleextends the other leg 62 toward the free end 24 e of the brake lever 24so as to form the positioning portion 62 b without bending the same andextends one leg 61 as bending the same to form the folded portion 61 dand to extend further therefrom so as to form the positioning portion 62b, wherein the positioning portion 62 b abuts against a peripheralsurface of the free end 24 e of the brake lever 24, and the brake lever24, after connecting the cable end 42 to the brake lever 24, isrestricted its rotation in the cable releasing direction. In thisexample, as in the previous third embodiment, the pair of the legs 61,62 resiliently fit on the strut-bridge 23 a by the spring force of thelegs 61, 62, and also the folded portion 61 d formed by bending one legs61 travels over the strut-bridge 23 a to abut against the end surfacethereof, thereby the clip 60 enfolding the strut-bridge 23 a. Althoughthis example illustrates the case in which the positioning portion 62 bof the clip 60 abuts against the peripheral surface of the free end 24 eof the brake lever 24, the positioning portion 62 b formed as extendingon an extension line of the other leg 62 may abuts against anintermediate portion of the brake lever 24.

Also, although the above-described embodiment illustrates the case inwhich the clip 60 is inserted from the side of the brake lever pivotalportion of the strut-bridge 23 a, the clip 60 may be inserted from theside of the strut superposing portion of the strut-bridge 23 a.

The mechanical brake actuator with regard to the fourth embodiment willbe explained with reference to FIG. 15.

The clip 60 as shown in FIG. 15 has the pair of the legs 61, 62 with theentire length longer than the lateral width of the strut-bridge 23 a andis designed such that positioning on the strut-bridge 23 a isaccomplished by the folded portions 61 d, 62 c formed by bending bothlegs 61, 62 around both ends and a positioning protrusion 61 e formed onone of or both legs 61, 62. Furthermore, the clip 60 has an extendingportion of the other leg 62 extending leftward from the positioningprotrusion 61 e, which functions as the positioning portion 62 b.

As the entire length of the clip 60 is set about two times longer thanthe lateral width of the strut-bridge 23 a and the positioningprotrusion 61 e is formed in the intermediate position thereof, the clip60 may be deflected leftward or rightward in the figure relative to thestrut-bridge 23 a for positioning.

When the clip 60 clips on the strut-bridge 23 a, the pair of legs 61, 62of the clip 60 is advanced from left relative to the strut-bridge 23 a,and the clip 60 is advanced deep enough for the positioning portion 62 bto abut against the inner surface of the strut-bridge 23 a (see the clip60 shown in two-dot chain line of FIG. 15), the positioning protrusion61 e abuts against the side end surface of a right side of thestrut-bridge 23 a to enfold thereof.

The amount/distance of extension of the positioning portion 62 b and thebrake lever 24 are interrelated so that when the clip 60 deflectsleftward in the figure relative to the strut-bridge 23 a, the rotationof the brake lever 24 in the cable releasing direction is restricted asthe positioning portion 62 b interferes the brake lever 24 at theposition where the entire brake cable connecting hole 24 f of the brakelever 24 is not exposed out from the opening of the strut 23. Also, theclip 60 is interrelated with the strut-bridge 23 a so that when the clip60 is deflected rightward in the figure relative to the strut-bridge 23a, the entire brake cable connecting hole 24 f of the brake lever 24becomes exposed out from the opening for inserting the connecting pin 43to connect the brake lever 24 and the cable end 42.

Upon completion of the connection between the brake lever 24 and thecable end 42, the clip 60 is pushed leftward in the figure as shown in asolid line of FIG. 15 to slide to position on the strut-bridge 23 a bythe folded portions 61 d, 61 c of both ends of both legs 61, 62 and thepositioning protuberance 61 e. By sliding the clip 60 to position on thestrut-bridge 23 a, the positioning portion 62 b formed on the clip 60projects toward the free end 24 e side of the brake lever 24, andtherefore the brake lever 24 interferes with the positioning portion 62b to restrict the rotation of the brake lever 24 in the cable releasingdirection.

The mechanical brake actuator relating to the fifth embodiment will beexplained with reference to FIG. 16 and FIG. 17. This embodimentillustrates an example of the clip 70 rotatably attached on thestrut-bridge 23 a, and connecting operation of the brake cable 40, thebrake lever 24, and the connecting pin 43 is possible when the clip 70is at the position in the cable releasing direction side, the clip 70restricts the rotation of the brake lever 24 to disable connectingoperation of the brake cable 40, the brake lever 24, and the connectingpin 43 when the clip 70 is at the position in the cable operatingdirection side. In other words, this embodiment is structured such thatwhen the clip 70 is at the position in the cable releasing directionside, once the brake cable 40, the brake lever 24, and the connectingpin 43 are connected, if the clip 70 is at the position in the cableoperating direction side, the connection among the three cannot bedisengaged.

More concretely, the clip shown in FIGS. 16 and 17 is such that theother leg 72 of the pair of facing legs 71, 72, which abuts against theinner surface of the strut-bridge 23 a, is designed shorter than the oneleg 71, and has the positioning hole 72 d, which positions as making theconvexo-concave fitting with the convex 23 i formed on the inner surfaceof the strut-bridge 23 a.

The one leg 71 is extended beyond the length of the strut-bridge 23 a,and the extended portion is bent to form a folded portion 71 d abuttableagainst the front end (left end in the figure) of the strut-bridge 23 aand at the same time to form the positioning portion 71 e after thefolded portion 71 d. This positioning portion 71 e abuts against thefree end 24 e of the brake lever 24 so as to restrict the rotation ofthe brake lever 24 in the cable releasing direction after connecting thecable end 42 with the brake lever 24.

When the clip 70 attaches on the strut-bridge 23 a, the pair of the legs71, 72 are inserted rearward relative to the strut-bridge 23 a (fromright side of the figure) to slid the clip 70 deeply thereover, and thepositioning hole 72 d of the other leg 72 fits over the convex 23 iformed on the inner surface of the strut-bridge 23 a, thereby making theconvexo-concave engagement to position the clip 70.

Entire length of one leg 71 of the clip 70 is designed such that thefolded portion 71 d formed at the free end thereof, unless forcedpressure is applied thereto, abuts against the front end (left end ofthe figure) of the strut-bridge 23 a, and one leg 71 maintain theposition in the cable releasing direction side. The folded portion 71 d,when the forced pressure is applied to rotate one leg 71, is designed toclip the front end (left end of the figure) of the strut-bridge 23 abetween a flat/straight surface and the folded portion 71 d of one leg71. Accordingly, the resilient deforming force of the folded portion 71d becomes a clipping force of the clip 70

Also, the length of extension of the positioning portion 71 e of theclip 70 and the strut-bridge 23 a is interrelated such that when one leg71 of the clip 70 is at the position in the cable releasing directionside, the entire brake cable connecting hole 24 f of the brake lever 24is exposed out from the opening of the strut 23.

The length of extension of the positioning portion 71 e and the brakelever 24 is interrelated such that when one leg 71 is at a position inthe cable operating direction side by force-pushing one leg 71 toapproach the outer surface of the strut-bridge 23 a, the positioningportion 71 e abuts against the peripheral edge of the free end 24 e,thereby restricting the rotation of the brake lever 24 in the cablereleasing direction after connecting the cable end 42 with the brakelever 24.

In addition to the same advantages as described in the first embodimentthat can be obtained in this example, the clip 70 can be furtherdownsized and manufactured by the simple bending process, therebydecreasing the material cost and the manufacturing cost of the clip 70.Furthermore, when the clip 70 attaching to the strut-bridge 23 a isrotated by fingers to restrict the rotation of the brake lever 24 in thecable releasing direction, the attaching sound and the resultedvibration make an operator to hear and feel the operation, therebyconfirming the clip installation.

Modification to the mechanical brake actuator of the fifth embodimentwill be explained with reference to FIGS. 18 and 19. This embodimentillustrates an example of the clip 70 rotatably attaching to the frontand rear end edges of the strut-bridge 23 a, and connecting operation ofthe brake cable 40, the brake lever 24, and the connecting pin 43 ispossible when the clip 70 is at the position in the cable releasingdirection side, the clip 70 restricts the rotation of the brake lever 24to disable connecting operation of the brake cable 40, the brake lever24, and the connecting pin 43 when the clip 70 is at the position in thecable operating direction side.

More concretely, the clip 70 as shown in FIGS. 18 and 19 has anengagement portion 73 between the pair of facing legs 71 and 72.

The other leg 72 abutting against the inner surface of the strut-bridge23 a is designed to be shorter than one leg 71 just like theabove-described fifth embodiment, but no positioning hole 72 d isnecessarily formed and then the other leg 72 can be shorter.

A first folded portion 71 d and a second folded portion 71 f arecontinuously formed in waveforms on the free end of one leg 71 extendingbeyond the strut-bridge 23 a, and the clip 70, as co-operating with theengagement portion 73, gradually clips on the front and rear end edges(left and right edges in the figure) of the strut-bridge 23 a.

Accordingly, the resilient deforming force of the first and secondfolded portions 71 d, 71 f becomes a clipping force of the clip 70relative to the front and rear end edges (left and right edges in thefigure).

The second folded portion 71 f in this example also functions as thepositioning portion which restricts the rotation of the brake lever 24in the cable releasing direction.

As shown in FIG. 18, when the second folded portion 71 f of the clip 70engages with the front and rear end edges (left and right edges in thefigure) of the strut-bridge 23 a, the clip 70 and the strut-bridge 23 ais interrelated so that the entire brake cable connecting hole 24 f ofthe bake lever 24 is exposed out from the opening of the strut 23.

As shown in FIG. 19, the length of extension of the second foldedportion 71 f as the positioning portion and the brake lever 24 isinterrelated such that when the first folded portion 71 d of the clip 70is engaged with the front end edge (left edge of the figure) of thebridging portion 23 a by force-pushing one leg 71 of the clip 70 toapproach the outer surface of the strut-bridge 23 a, the second foldedportion 71 f abuts against the peripheral edge of the free end 24 e ofthe brake lever 24, thereby restricting the rotation of the brake lever24 in the cable releasing direction after connecting the cable end 42with the brake lever 24.

The above-described clips 30, 50, 60 and 70 of this invention are notlimited to examples of the spring steel clip as long as functioning as amember to attach to the strut-bridge, for example a plastic clip maysufficient.

It is readily apparent that the above-described embodiments have theadvantage of wide commercial utility. It should be understood that thespecific form of the invention hereinabove described is intended to berepresentative only, as certain modifications within the scope of theseteachings will be apparent to those skilled in the art. Accordingly,reference should be made to the following claims in determining the fullscope of the invention.

1. A mechanical brake actuator, comprising: a strut that has two facingplates with a strut-bridge connecting therebetween and that engages onebrake shoe; a plate-like brake lever that engages with the other brakeshoe, where said brake lever is retained in a space between said facingplates of the strut and is pivotally supported in the strut at aproximal end thereof; and said brake lever and said strut relativelyrotate to spread apart from each other while pulling a brake cableconnected to a free end of the brake lever via a connecting pin, whereina clip, which restricts rotation of said brake lever in a cablereleasing direction, attaches to said strut-bridge.
 2. The mechanicalbrake actuator according to claim 1, wherein said clip has a pair oflegs that clip on the strut-bridge.
 3. The mechanical brake actuatoraccording to claim 1, wherein said clip enfolds said strut-bridge. 4.The mechanical brake actuator according to claim 2, wherein said clipenfolds said strut-bridge.
 5. The mechanical brake actuator according toclaim 2, wherein said clip has a positioning portion that restricts therotation of the brake lever in the cable releasing direction as abuttingone portion of the leg against the brake lever.
 6. The mechanical brakeactuator according to claim 2, wherein said clip slidably clips on thestrut-bridge.
 7. The mechanical brake actuator according to claim 6,wherein said clip and said strut-bridge have two pairs ofconvexo-concave engagement and each pair of said convexo-concaveengagement is to be selectable as sliding the clip.
 8. The mechanicalbrake actuator according to claim 6, wherein a connecting operation ofthe brake cable, the brake lever, and the connecting pin is possiblewhen said clip is at a retreat position, and the clip restricts therotation of the brake lever so as to disable the connecting operation ofthe brake cable, the brake lever, and the connecting pin when said clipis at a progress position.
 9. The mechanical brake actuator according toclaim 7, wherein a connecting operation of the brake cable, the brakelever, and the connecting pin is possible when said clip is at a retreatposition, and the clip restricts the rotation of the brake lever so asto disable the connecting operation of the brake cable, the brake lever,and the connecting pin when said clip is at a progress position.
 10. Themechanical brake actuator according to claim 1, wherein said cliprotatably attaches to the strut-bridge.
 11. The mechanical brakeactuator according to claim 2, wherein said clip rotatably attaches tothe strut-bridge.
 12. The mechanical brake actuator according to claim10, wherein the clip and the strut-bridge have a convexo-concaveengagement, and said clip attaches to the strut-bridge as fitting theconvexo-concavo portions.
 13. The mechanical brake actuator according toclaim 11, wherein the clip and the strut-bridge have a convexo-concaveengagement, and said clip attaches to the strut-bridge as fitting theconvexo-concavo portions.
 14. The mechanical brake actuator according toclaim 10, wherein said clip clips on the front and rear end edges of thestrut-bridge.
 15. The mechanical brake actuator according to claim 11,wherein said clip clips on the front and rear end edges of thestrut-bridge.
 16. The mechanical brake actuator according to claim 10,wherein the connecting operation of the brake cable, the brake lever,and the connecting pin is possible when said clip is at a position inthe cable releasing direction side, and the clip restricts the rotationof the brake lever to disable the connecting operation of the brakecable, the brake lever, and the connecting pin when said clip is at aposition in the cable operating direction side.
 17. The mechanical brakeactuator according to claim 11, wherein the connecting operation of thebrake cable, the brake lever, and the connecting pin is possible whensaid clip is at a position in the cable releasing direction side, andthe clip restricts the rotation of the brake lever to disable theconnecting operation of the brake cable, the brake lever, and theconnecting pin when said clip is at a position in the cable operatingdirection side.
 18. The mechanical brake actuator according to claim 12,wherein the connecting operation of the brake cable, the brake lever,and the connecting pin is possible when said clip is at a position inthe cable releasing direction side, and the clip restricts the rotationof the brake lever to disable the connecting operation of the brakecable, the brake lever, and the connecting pin when said clip is at aposition in the cable operating direction side.
 19. The mechanical brakeactuator according to claim 13, wherein the connecting operation of thebrake cable, the brake lever, and the connecting pin is possible whensaid clip is at a position in the cable releasing direction side, andthe clip restricts the rotation of the brake lever to disable theconnecting operation of the brake cable, the brake lever, and theconnecting pin when said clip is at a position in the cable operatingdirection side.
 20. The mechanical brake actuator according to claim 14,wherein the connecting operation of the brake cable, the brake lever,and the connecting pin is possible when said clip is at a position inthe cable releasing direction side, and the clip restricts the rotationof the brake lever to disable the connecting operation of the brakecable, the brake lever, and the connecting pin when said clip is at aposition in the cable operating direction side.
 21. The mechanical brakeactuator according to claim 15, wherein the connecting operation of thebrake cable, the brake lever, and the connecting pin is possible whensaid clip is at a position in the cable releasing direction side, andthe clip restricts the rotation of the brake lever to disable theconnecting operation of the brake cable, the brake lever, and theconnecting pin when said clip is at a position in the cable operatingdirection side.